Outdoor Cook Stove

ABSTRACT

A portable outdoor stove is provided which includes a burner primarily comprising an outer and inner pieces bolted tightly to form a small gas/air mixture chamber for accepting and maintaining high pressure gaseous fuel, a wind guard of cylinder shape capable of tightly coupled with a cooking vessel and possessing slot opening of less than 180° toward its top for exhaust outlet, adjustable means for supporting the burner and positioning flame from burner onto bottom of cooking vessel, short or long legs to support the wind guard and the cooking vessel. A protection guard can be put around the first wind guard preventing an operator accidentally touching the wind guard during cooking.

US PATENT DOCUMENTS 4,062,341 December 1977 Panzarella 126/41 R 5,158,067 October 1992 Dutro et al. 126/39 R 6,234,064 May 2001 Turrel  99/323.9 6,098,611 August 2000 Filmore 126/50 D386,936 December 1997 Stone et al. D7/332 4,553,524 November 1985 Wheat et al. 126/25 R 4,353,347 October 1982 Seed 126/41 R 5,775,316 July 1998 Jones 126/41 R 4,555,616 November 1985 O'Brien 219/432 5,044,352 September 1991 Lok 126/39 R 5,226,406 July 1993 Reynolds 126/39 R 4,583,941 April 1986 Elperin et al.  41/347 5,315,983 May 1994 Law 126/216 3,759,164 September 1973 Robinson  99/413 4,108,142 August 1978 Barson et al. 126/41 R 5,992,407 November 1999 Tsai 126/40 6,439,107 August 2002 Bourgeois  99/340 6,725,856 April 2004 Barbour et al 126/50 6,832,607 December 2004 Zhou 126/30 6,619,280 September 2003 Zhou 126/39 R

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an outdoor cook stove utilizing high pressure gaseous fuel, in particular a stove for domestic or industrial gas cooking using bottled gas, and is suitable for round bottom cooking vessels.

2. Brief Description of the Prior Art

There are various attempts for outdoor stove manufacturers to accommodate cooking for round bottom vessels such as a wok. Barbecue equipment makers make wok adapter to sit on top of fire grid. However the fire grid is not powerful enough and the entire structure is not efficient enough for wok cooking. Authentic, restaurant quality oriental wok cooking requires a stove capable of generating more than 100,000 BTU in power. Such power is beyond reach of single ring low pressure gas stoves. In commercial and industrial wok cooker, as partially illustrated in U.S. Pat. No. 5,315,983, either multi-rings or multiple jet burners are used to achieve the necessary power. Another drawback of using low pressure gaseous fuel is its stove being more susceptible to wind during outdoor cooking.

U.S. Pat. Nos. 5,158,067 and 4,062,341 taught outdoor stove construction for wok cooking. However they share several disadvantages that prevent them from reaching high quality oriental cooking. The first is the low pressure gaseous fuel which prevents their stoves from reaching 100,000 BTU in power. The second disadvantage is the low pressure burner which they utilize does not have center flame heating to the bottom of a wok. As with a bowl shape, it is most important to direct the burning flame toward the bottom of a wok for efficient heat transfer. The disadvantage of not using a center flame is in many burner designs, for example U.S. Pat. Nos. 6,234,064, 6,098,611, D386,936, 4,553,524, 4,353,347. The flame coming out from all these burners spread outward, leaving a sizable center portion of the cooking vessel relying on metal conducting heat back to its center. For a wok, this heat conducting downward to its bottom is extremely inefficient.

Yet another disadvantage of the aforementioned stove constructions is to allow the flame to extend above the wok along its outside surface. Since wok cooking requires an operator to stay closely and maneuver the wok in different ways, the flame coming out can easily burn and hurt the operator. Such examples can be found in U.S. Pat. Nos. 4,062,341, 6,098,611, 5,775,316, 3,759,164, 5,992,407, 6,439,107 and 6,725,856. Because of this reason, the operator is forced to reduce power of the stove to stay safe. For low pressure gaseous stove ranges like in U.S. Pat. Nos. 5,044,352 and 5,226,406, expensive exhaust duct mechanism is built for routing the flame and exhaust away from the operator.

U.S. Pat. Nos. 6,234,064, 6,098,611, D386,936, 4,555,616, 4,353,347 and 4,108,142 taught to have fixed center burner position with respect to bowl shape cooking vessel. Such fixed position defines fixed heating power distribution to the vessel, forcing the operator to frequently toss foods to various locations in order to receive different heating power. Fixed position between stove and wok greatly restricts the freedom for the operator to tilt and rotate the wok for various food items to receive different flame power, which is necessary when the food items are too fragile to be tossed.

U.S. Pat. No. 4,583,941 taught a burner construction on how to form flame inwardly around an imaginary cylinder. Although the flame is inwardly directed, it still does not heat the center portion of its cooking vessel. Another drawback is that as required by its inward flame, the burner has a bigger chamber for pre-mixed gaseous fuel and air. This big chamber inevitably reduces the mixture gas pressure and hence the power of the burner.

U.S. Pat. No. 5,979,428 teaches a retrofitable wind screen for portable stove which is wrapped around the original stove body. This is wrap around wind screen is not study at all to withstand a round bottom vessel.

U.S. Pat. No. 5,315,983 teaches a two piece support ring structure for supporting a wok cooking vessel on top of a burner cylinder of a cooking range. Between these two pieces of ring structure some windows can be formed on the back of the range for exhaust. U.S. Pat. No. 6,832,607 shows an outdoor cook stove with a wind guard of two windows at its back for flame outlet. The top bars of the windows in both U.S. Pat. Nos. 5,315,983 and 6,832,607 are subjected to high temperature flames and thus are the most vulnerable for damage. Besides, these top bars block the flame to reach the wok underneath surface. This blockage is an efficiency loss.

It is the objectives of the present invention to overcome aforementioned drawbacks.

SUMMARY OF THE INVENTION

The first objective of the present invention is to utilize high pressure gaseous fuel to achieve highest power for wok cooking with simple burner construction to save cost significantly over traditional high power wok cookers with low pressure gaseous fuel.

The second objective of the present invention is to construct an outdoor stove with a wind guard ring tightly hosting a wok. A portion of the wind guard has openings close to the wok for directing out the flame and exhaust. To increase cooking efficiency and product life cycle, such openings do not have top bars to block burner flamer from reaching underneath surface of the cooking vessel. It also provides access for burner ignition. This portion is to be positioned away from the operator during operation. The rest portion of the wind guard does not have opening to prevent any flame from extending along its side. The operator is positioned along this side for safe operation. This wind guard defines the heating area to the wok and is sized around 9″-13″ in diameter for commonly available woks.

The third objective of the present invention is to add a second ring outside the first wind guard to prevent the operator from accidentally touching the hot surface of the first wind guard.

The fourth objective of the present invention is to construct a stove to give complete freedom to the wok operator. The wok is not required to be fixed in position to the stove. The operator can tilt and move the wok in his/her own will at any time in order to achieve best cooking result.

The fifth objective of the present invention is to have burner position adjustable within the stove to accommodate both round and flat bottom cooking vessels for optimum heat transfer.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention will now be described in connection with certain preferred embodiments with reference to the following illustrative figures so that it may be more fully understood.

With specific reference now to the figures in detail, it is stressed that the particular shown are by way of example and for purpose of illustrative discussion of the preferred embodiments of the present invention only. They are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention. The description together with the drawings should make it apparent for those skilled in the art how the several forms of the invention may be embodied in practice. In the drawings:

FIG. 1 is a prior art showing a two-piece support ring structure for supporting a wok cooking vessel on top of a burner cylinder of a cooking range. The ring structure supports the wok cooking vessel and forms flame windows with top bars.

FIG. 2 is a prior art showing an outdoor cook stove with a wind guard having flame windows. The wind guard supports a cooking vessel. The flame windows have top bars.

FIG. 3A is a perspective view of a first preferred embodiment of an outdoor stove incorporating a high pressure gaseous burner, as well as a wind guard ring and an adjustable metal strip for holding the burner.

FIG. 3B is a side elevated view of the embodiment of FIG. 3A showing how the burner is bolted on the strip.

FIG. 3C is a top view of the embodiment in FIG. 3A showing details of the mounting strip and three supporting legs.

FIG. 4 is a perspective view of a second preferred embodiment of an outdoor stove with a second wind guard ring encircling the first ring of FIG. 3A.

FIG. 5 is a perspective view of a third preferred embodiment which incorporates the short leg preferred embodiment of FIGS. 3A and 3 long legs for form a long leg version.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 3A illustrates an outdoor stove 80 constructed according to the preferred embodiment of the present invention. Although stove 80 is specially designed to handle outdoor cooking using a round bottom cooking vessel, stove 80 is also suitable for flat bottom vessel cooking. Stove 80 includes a preferred converging flame burner 10 of U.S. Pat. No. 6,619,280. Burner 10 is mounted on a metal bar 130 using the same bolt 30, nut 32 and washer 34, as in FIG. 3B. Burner 10 directs its flames inward and upward to a concentrating point. This point can be aligned with the bottom of a wok by metal bar 130. Metal bar 130 has a horizontal section 134. In the center of 134 a hole is drilled for bolt 30 to come through, better viewed in FIG. 3B. Burner 10 is mounted on 134 and position of the venturi pipe 24 can be adjusted horizontally for convenient inlet of gas pipe 70. Metal bar 130 also includes two vertical sections 132 and 136 at both ends, as viewed in FIG. 3C. These two vertical sections 132 and 136 have slot openings. For example, vertical 132 has a slot 138. Two bolts 140, 142, two nuts 150, 152 and two washers 160, 162 are used to fasten the slot 132 to a supporting ring 100. Similar construction is done on another side 136. Vertical positioning of the metal bar 130 along ring 100 is accomplished by adjusting the slots with respect to the bolts. In this way the concentrating flame point can always be adjusted to touch the bottom of various woks and other round bottom vessels. The length of section 134 is about the same as the diameter of ring 100.

Ring 100 serves multiple purposes. It can support a wok for cooking. A wok can sit right on ring 100. The diameter for ring 100 is preferably between 9″ to 13″. Ring 100 is constructed as a cylinder shape to house a wok with minimum gap. After heating the bottom of the wok, the concentrated combustion flame is split up along the wok underneath surface. Because of small gap between wok and ring 100, the flame is not able to penetrate out of the gap. Instead, it is forced to use windows 120 and 122 for exhaust purpose. It should be noted that 120 and 122 are just slots cut into ring 100. By putting a wok on top of ring 100, windows 120 and 122 are formed between the opened slots and underneath surface of the cooking wok. In this way the ring defines the heating area to the wok. And the flame coming out of windows 120 and 122 continues to heat the wok. Since windows 120 and 122 have limited opening on ring 100, their openings define limited unsafe area for an operator. When an operator is working away from these openings (windows 120 and 122), there is no flame coming up along the outer surface of the wok to cause any harm to the operator.

The total opening angle along ring 100 is preferably less than 180° such that no direct wind can blow through burner 10. In this way ring 100 serves as a wind guard. Ring 100 also supports metal bar 130 for burner 10. Four holes are drilled for mounting bolts for slots along 132 and 136.

Ring 100 is further supported by three legs 110, 112 and 114. Construction for each leg is similar. A bend at 116 for leg 110 in FIG. 3B is to increase its bottom perimeter to enhance stability of the entire stove 80. Top end 110A of leg 110 is welded to a lower position of ring 100. Legs 110, 112 and 114 are preferably spread out in 120°.

To start cooking, high pressure gaseous fuel is supplied through a high pressure regulator. Ejected combustion gas and air mixture from the burner can be ignited by an outdoor igniter through either ring windows 120, 122 while a wok is already sitting on top of ring 100. Alternately, the wok can be temporally moved away for an igniter to ignite the flame through top of ring 100.

A second stove embodiment of the present invention is shown generally in FIG. 4. Since ring 100 prevents flame from burner 10 to reach the operator on the opposite side of windows 120 and 122, the heat is trapped within ring 100 for the energy to be transferred to a wok. When burner 10 is adjusted to its upper power range, ring 100 may warm up and be hazardous to touch. Although there is little chance for the operator to touch ring 100 because the operation is accomplished by using wok handles at least half foot away from ring 100, a second ring 200 can still be added outside of ring 100 to protect ring 100 from being reached. Various mounting technique can be used for ring 200. Three metal pieces 210, 212 and 214 are welded upwardly on legs 110, 112 and 114. Piece 210 and leg 110, piece 212 and leg 112, piece 214 and leg 114 together define three junction points for ring 200 to rest on. The height of ring 200 is constructed lower than that of ring 100, preferably half inch. In this way a wok is still supported by ring 100 and exhaust flame can still come out from windows 120 and 122. Aforementioned features of ring 100 are preserved. Since ring 200 is not heated by flame from burner 10, it will remain cool during on-going cooking process. An alternate mounting for ring 200 is to weld it directly on legs 110, 112 and 114. Ring 200 does not need to be solid, it can be perforated as long as it can prevent the operator's fingers to reach in to ring 100.

A third stove embodiment of the present invention is shown in FIG. 5. The three short legs 110, 112 and 114 of the first embodiment of the present invention in FIG. 3A are connected to three long legs 170, 172 and 174 through couplers 180, 182 and 184 (not shown in FIG. 5). Each short leg and long leg are plugged into the two ends of a coupler, i.e., short leg 110 going into the top end of coupler 180 while long leg 170 into the bottom end of the same coupler 180. Finally both short and long legs are fastened by screws. For example, short leg 110 is fastened to coupler 180 by screw 190 while long leg 170 is fastened to couple 180 by screw 192. In this way the short leg version of FIG. 3A and three long legs 170, 172 and 174 for a study long leg version.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive. The scope of the invention will be indicated by the appended claims rather than by the foregoing description. And all changes, which come within the meaning and range of equivalency of the claims, are therefore intended to be embraced therein. 

1. A portable outdoor stove for cooking foods comprising: a burner accepting pressured gaseous fuel to produce high power output, and ejecting combustion flame through holes, directing their flames to a center area above, a cylinder shape wind guard surrounding the said burner readily accepting a cooking vessel, and a small gap being formed between the guard and the said vessel tight enough to prevent flame coming out to hurt operator, the said guard having slots opened toward its top on opposite side of the operator, these slots and bottom side of the cooking vessel forming windows to let out exhaust flame, such windows allowing the flame to continue to heat the cooking vessel and yet still preserving the said wind guard function, a means to support the said wind guard, and a means to support the said burner for aligning said center area of said flames to said bottom of said vessel, whereby said flames deliver highest heating power to bottom of said cooking vessel in a safe and stable manner.
 2. The stove of claim 1, wherein said cooking vessel can be a wok, or any round bottom and flat in shape.
 3. The stove of claim 1, wherein the said supporting means for said wind guard comprises three simple legs;
 4. The stove of claim 3, wherein each of the three simple legs further comprises one short leg, coupled with one long leg with coupler where screws are used to tighten the short leg and the long leg to the coupler;
 5. The stove of claim 1, wherein the supporting means for said burner comprises a metal bar with vertical ends. The ends of said metal bar have slot openings and can be mounted with bolts on said wind guard. The relative position of said bar is adjustable by relatively positioning said slot openings with respect to bolts on said wind guard.
 6. The stove of claim 5, wherein the said burner is mounted on center of said metal bar and can be rotated with respect to a mounting bolt in said center.
 7. The stove of claim 1, further comprising a means to surround said wind guard to prevent the operator from accidentally touching said wind guard during cooking. 